Extra virgin olive oils obtained from the Ayvalık, Memecik, Gemlik, Çekişte, and Sarı Ulak Turkish cultivars were evaluated to determine their chemical composition, quality classification, authenticity indicators, and sensory characteristics. Standard quality parameters, including free fatty acidity, peroxide value, and ultraviolet absorbance (K232, K270), were analyzed in accordance with International Olive Council (IOC) regulations. The majority of the samples met the criteria for extra virgin olive oil. The oleic acid content varied by variety and region, with Ayvalık and Memecik showing notably high levels. Sterol profile analyses revealed distinctive chemical markers that indicate authenticity and quality. Sensory analysis results showed that regional differences had a significant impact on aroma, taste, and overall acceptability. Oils from Ayvalık and Memecik received high scores for positive sensory attributes such as fruitiness, bitterness, and pungency. The results show that the chemical and sensory qualities of olive oil are directly influenced by both genetic diversity and growing conditions, which underscores the importance of conserving local varieties and promoting regional production methods.